Timing device



March 26, 1946. w. R. 'TALIAFERRO TIMING DEVICE Filed March 18, 1944INVENTOR William R 7E1I iaferro.

ATTORNEY WITNESSES:

. magnetic flux decay.

PatentedMar. 2c, 1946 TIMING DEVICE William B. Taliaferro, Edgewood,Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh,Pa., a corporation of Pennsylvania Application March 18, 1944, SerialNo. 527,116

8 Claims.

My invention relates to timing devices and par ticularly to timingrelays to be used in electric circuits.

The known and customary timing devices contain as a'rule a timingmechanism such as a clockwork, escapement or flywheel device, or thedelay between the actuation of the device and the desired functionperformed thereby is obtained by electromagnetic means such as a shortcircuited winding on a magnet core. Devices equipped with an escapementor the like mechanism are rather intricate and space consuming, whileshort-circuited windings; as a rule, require alternating currentexcitation and permit obtaining only limited timing periods. In caseswhen direct-current excitation is to be employed, only very short timingperiods are obtainable with the known devices of simple design, and thetiming is as a. rule effective only when the excitation is switched onor oil but not under both conditions of operation.

It is an object of my invention to provide a timing device which permitsobtaining a period of delay within wider limits than those possible bydirect current relays with short circuited windings and other means ofproducing a delayed More particularly, my invention aims at obtainingdevices of long timing periods which do not require the use of anescapement or the like mechanism.

Another object of the invention is to devise a timing relay which isapplicable for both alternating current and direct current excitation.

Still another object is to provide an electromagnetic timing device orrelay which operates upon energization as well as on deenergization ofits control magnet, or which secures a desired timing period under bothcontrol conditions.

In order to achieve these objects my invention takes advantage of theso-called cold-flow properties of plastic materials, in particularcompositions of resinous nature. It is well known that when such amaterial is subjected to steady deterials can also be used, provided thematerial is in a relatively low' state of polymerization or containsplasticizers or modifiers in a suflicient amount to secure the necessarycold-flow deformation.

The stress produced by the actuating or control means of a relay ortiming device according to the invention may act in compression orexpansion or produce torsional or bending stress on the coldflowingplastic material, and the shape and dimensions of this material arechosen with respect to the stress so that the resulting deformationassumes a given magnitude within the desired timing period. Theconfiguration ofthe body of cold-flowing material may be chosenaccording to the needs of each intended application, for instance, itmay form a spiral, helix, diaphragm, rod or bar.

The invention will be more fully understood from the followingdescription of the embodiment illustrated in the drawing in which Figure1 shows a partly sectional view of an electromagnetic timingrelay, whileFigs. 2 and 3 represent a top view and a lateral sectional view of thecoldflowing body and some elements of the appertaining assembly.

According to the drawing, a substantially U- shaped support I of rigidmaterial, for instance iron or brass, carries a movable arm structure 2which forms two parallel legs 3 and 4 each providedwith outwardlyextending studs 5 and 6, respectively. These studs are pivoted inangular journals 1 and l which are rigidly secured to thesupport I.

A transversely extending brazing section 9 of r the arm structure 2forms an eye at HI, and a similar section H is Provided with an eye l2.A third transverse section l3 serves to render the arm structuresufllciently ri d.

An insulating pin ll is firmly mounted on the peripheral end of the armstructure 2 and serves to actuate the contact means mentionedhereinafter.

An extension spring Ii of helical shape is attached to support I andengages eye M. A second helical extension spring i5 connects eye l2 withthe armature l? of an electromagn'et whose magnet frame i8 is firmlysecured to the supp rt 6. The magnet coil is denoted by ES.

An insulating member 20 is firmly secured between the legs of thesupport i so as to form a rigid supporting structure for two pairs ofcontacts denoted by 2|, 21 and 23, 2|, respectively.

The above-mentioned body 0! coldefiowlng plastic material consists of abar 25 of rectangular cross section. Tins bar is clamped to the supportl by means of a sleeve 28. The other end of bar engages a similar sleeve2?. Sleeve 2? is pro vided with studs 28 and 29 which engage elongatedholes of the legs 3 and it such as the hole denoted by in Fig. 1. Due tothis design, the bar 25 is subjected essentially only to bending stressduring the operation of the relay.

When the coil it! is deen'ergizeol the spring 05, acting as a return orbiasing device, holds the arm structure 2 in the position shown in. Fig.l. in this position the insulating pin it rests against contact 22 andthereby closes the circuit between contacts 20 and 22.. When cell it isenergized it attracts the armature it immediately and thus puts thespring it under tension. .The force of spring it is so chosen that itexceeds the biasing force of spring in and hence tends to move the.

arm structure 2 downwardly, However, the coldfiowing body 25 prevents animmediate motion of the arm structure, but, under the continuous forceproduced by the electromagnet, yields grad ually so that at first theengagement between contacts 2i and i2 is opened. Upon elapse-of a timingperiod, the engagement between contacts upon elapse of a timingperiocl,contacts 2i and 22 are closed.

It will be apparent from the above described on ample of my inventionthat the timing period provided by the cold-donning body can be variedwithin wide limits by selecting the distance between the contacts orstops and thereby the degree of deformation necessary for obtaining theintended control operation. recognized from the example that the timingperiod is also dependent on the force of the biasing means and the forceproduced by the electromagnetic actuating device. Consequently thetiming period can also be varied by a proper selection or adjustment ofthe actuating and biasing means. In order to permit such an adjustmenttwo adjust= ing screws ti and 32 are provided. The screw 8i permitsvarying the travel of the armature ill and hence the force exerted byspring it on arm structure 2 when the coil ill is energized. The screw32 permits varying the biasingiorce ex erted on the arm structure by thespring 05.

A third way of varying or adjusting the time period consists inselecting the dimensions of the body 25. For instance, a smaller crosssection and a greater length of the bar result in a reduced timingperiod while an increase in cross section or reduction in length has theopposite efiect.

As mentioned previously, thetiming period is also determined by theselected composition of the cold-flowing material. A large number ofsuch substances are known and available. Appllcable for the purposeoi-my invention are. for instance, vinyl chloride resins, polystyreneresins, copoiymers of vinyl acetate and vinyl chloride, methylmethacrylate, cellulose acetate.- nylon resins, copolymers of styreneand modified "glycolmaleatc esters.

Timing devices according to my inventionhave also the advantage thatthey are. inherently shockproor". For instance, when c. relay as illus-=trated in the drawing is subjected to impact shock,

Slit

It will further be assume for instance, on board oi ship or on vehicles,the shock forces and vibrations caused by the impact are either of shortduration or of high frequency as compared with the normal operation ofthe relay by the continuous force produced by the electromagnetic orother actuating device, or by the biasing effect of the return spring,The cold flowing body oiiers an extremely high resistance toshort-lasting or high-frequency stresses. Consequently, the movableassembly of the device, even if not dynamically balanced, tends toretain itspreshock position but permits the actuating magnet to performits normal function even during the persistence of shock iorcesorvibrations. In this respect, devices according to my invention aresimpler and more eflectiv'e than many of those heretofore proposed foruse under conditions where impact shocks are to be expected.

in view of the fact that timing devices ac cording to my inventioncanlce modified in various respects by those skilled in the withoutdeparting from the objects, advantages and nrin= ciples of my inventiomlwish this specification to be understood as illustrative rather than ina limiting sense.

I claim as my invention: l. A timing relay comprising a body of resinous-cold=-iiowing thermoplastic material, an electro magnetic actuatingdevice having a movable armature connected with said body ionsubjectingit to cold-flow deformation, and contact means disposed on saidstructure relative to said body so as to be controlled thereby uponoccurrence of a given cold-flow deformation of said body.

2. A timing device comprising a stationary structure, a body ofcold-flowing resinous plastic material having one end secured to saidstructure, an electric actuating device having a movable actuatingmember connected with the other end of said body for subjecting it tocold-flow defor mation when operative, and contact means controlled bysaid body in dependence upon its deformation for controlling a circuitupon elapse of a'period of given cold flow deformation.

3. A timing relay comprising a stationary structure, a body ofcold-flowing resinous plastic material having one end secured to saidstrum ture, an electromagnetic actuating device having an armatureconnected to the other end of said body for subjecting it to bendingdeformation when operative, and contact means disposed on said'structurein the path oi the deforming mo tion of said bodysc as to be actuatedthereby upon a given deformation thereof.

4. A timing relay comprising a stationary structure, an elongated bodyof cold-flowing thermoplastic material having one end secured to saidstructure, a controllable source of mechanical power connected to theother end of said body for subjecting it to cold-flow deformation in agiven direction, biasing means connected with said body for subjectingit to cold-flow deformation in the opposite direction, and contact meanstime-controlled by said body so as to be actuated in dependence upon agiven deformation thereof.

5. A timing relay comprising a stationary structure, a body ofcold-flowing resinous plastic material having one end secured to saidstructure,

an electromagnetic actuating device having an armature connected to theother end of said body said body for subjecting it to cold-flowdeformation in the opposite direction, and contact means time-controlledby said body so as to be actuated in dependence upon a given deformationthereof.

6. A timing relay comprising a stationary str dcture, a body ofcold-flowing resinous plastic material having one end secured to saidstructure, an electromagnetic actuating device having an armature and aspring connecting said armature with said body for subjecting it tocold-flow deformation in a given direction, a biasing spring connectedwith said body for subjecting it to coldflow deformation in the oppositedirection, and contact means time-controlled by said body so as to beactuated in dependence upon a given: deformation thereof.

7. A timing relay comprising a stationary structure, a rigid memberhaving one end pivoted to said structure, means for biasing said membertowards a given pivotal position, a controllable source of mechanicalpower connected with said member for moving it in opposition to saidbiasing means, a body of cold flowing plastic material disposed betweensaid structure and saidmem ber so as to retard the angular motion ofsaid member produced by one of said biasing means and said sourcerespectively, and contact means disposed relatively to said member so asto be actuated thereby upon occurrence of a given pivotal travelthereof.

8. A timing relay comprising a stationary structure, a rigid memberhaving one end pivoted to said structure, means for biasing said membertowards a given pivotal position, an electromagnetic actuating devicehaving an armature and a spring connecting said armature with saidmemher for moving it in opposition to said biasing means, a body ofresinous thermoplastic material disposed between said structure and saidmember so as to retard the angular motion of said member produced by oneof said biasing means and said source respectively, and contact meansdisposed relatively to said member so as to be actuated thereby uponoccurrence of a given pivotal travel thereof.

WILLIAM R. TALIAFERRO.

